they can't see clearly because their eyesight is poor改为简单句

they can't see clearly because their eyesight is poor改为简单句
they can't see clearly because their eyesight is poor
改为简单句

they can't see clearly because their eyesight is poor改为简单句
They can't see clearly because their eyesight is poor.
They can't see clearly because of their poor eyesight.
他们看不清楚,因为他们视力很差.
because用于引导状语从句,because of后则是接词或短语.